Reciprocating pistons of piston-type compressor

Abstract

A piston-type compressor has seven cylinder bores formed in a cylinder block which is formed in a compressor housing. A piston is slidably disposed within each of the cylinder bores. Each of the pistons includes a cylindrical main body and an engaging portion axially extending from the cylindrical body. A drive shaft is rotatably supported in the cylinder block. A bearing couples the plate to each of the pistons, so that the pistons reciprocate within the cylinder bores upon rotation of the plate which is tiltably connected to the drive shaft. A recessed portion is formed in an interior of the cylindrical body of each piston so that the cylindrical body forms a C-shaped cross-section perpendicular to longitudinal axis of the piston. Therefore, the configuration obtains lightweight pistons while simultaneously maintaining the efficiency of the compressor.

What is claimed is: 
     
       1. A piston-type fluid displacement apparatus comprising: a housing enclosing a crank chamber, a suction chamber, and a discharge chamber, said housing including a cylinder block wherein a plurality of cylinder bores are formed;   a drive shaft rotatably supported in said cylinder block;   a plurality of pistons, each of which is slidably disposed within one of said cylinder bores, each of said pistons including a cylindrical body and an engaging portion axially extending from a first axial end of said cylindrical body;   a plate having an angle of tilt and tiltably connected to said drive shaft;   a bearing coupling said plate to each of said pistons, so that said pistons reciprocates within said cylinder bores upon rotation of said plate; and   a recessed portion formed in an interior of said cylindrical body of each said piston, said recessed portion extending from said engaging portion to a head of said piston, so that said cylindrical body has a C-shaped cross-section perpendicular to a longitudinal axis of said piston.   
     
     
       2. The piston-type fluid displacement apparatus of claim 1, wherein said piston includes an aperture formed in a periphery surface of said cylindrical body, so that said aperture is in fluid communication with said recessed portion of said piston. 
     
     
       3. The piston-type fluid displacement apparatus of claim 1, wherein said cylindrical body of said piston includes a periphery surface coated with a self-lubricating coating. 
     
     
       4. The piston-type fluid displacement apparatus of claim 3, wherein said self-lubricating coating is polytetrafluoroethylene. 
     
     
       5. The piston-type fluid displacement apparatus of claim 1, wherein said piston includes at least one annular groove formed on said periphery surface of said cylindrical body. 
     
     
       6. The piston-type fluid displacement apparatus of claim 5, wherein said piston includes at least one piston ring disposed in said annular groove. 
     
     
       7. The piston-type fluid displacement apparatus of claim 6, wherein said at least one piston ring comprises a self-lubricating material. 
     
     
       8. The piston-type fluid displacement apparatus of claim 7, wherein said self-lubricating material is polytetrafluorethhylene. 
     
     
       9. The piston-type fluid displacement apparatus of claim 3, wherein said piston includes at least one annular groove formed on said periphery surface of said cylindrical body. 
     
     
       10. The piston-type fluid displacement apparatus of claim 9, wherein said piston includes at least one piston ring disposed in said annular groove. 
     
     
       11. The piston-type fluid displacement apparatus of claim 10, wherein said at least one said piston ring comprises a self-lubricating material. 
     
     
       12. The piston-type fluid displacement apparatus of claim 11, wherein said self-lubricating material is polytetrafluoroethhylene.